Fix: Allow the usage of frozenset in the isin(...) and notin(...) functions

[antoninkriz]

This merge request should allow users to use .isin(...) and .notin(...) functions with frozenset as an argument.

Current behavior throws an error as in this minimal reproducible example:

>>> from pypika import Table, Query
>>> best_customers = frozenset([1, 2, 3])
>>> customers = Table('customers')
>>> Query.from_(customers).select(customers.id, customers.name).where(customers.id.isin(best_customers))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/utils.py", line 50, in _copy
    result = func(self_copy, *args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/queries.py", line 930, in where
    if not self._validate_table(criterion):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/queries.py", line 1155, in _validate_table
    for field in term.fields_():
                 ^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/terms.py", line 57, in fields_
    return set(self.find_(Field))
               ^^^^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/terms.py", line 37, in find_
    return [node for node in self.nodes_() if isinstance(node, type)]
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/terms.py", line 37, in <listcomp>
    return [node for node in self.nodes_() if isinstance(node, type)]
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/REDACTED_PATH_TO_PYTHON/python3.11/site-packages/pypika/terms.py", line 795, in nodes_
    yield from self.container.nodes_()
               ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'frozenset' object has no attribute 'nodes_'
>>> 

[AzisK]

Could you add a test for this feature?

[antoninkriz]

@AzisK done, tests added ✔️

[AzisK]

Looks good. I am merging this but the version will be bumped later. Thanks for your effort